Structural members are made from many materials and take many forms. Since the present invention is to be illustrated by means of a tennis racket such structural members as described will be related thereto. Tennis rackets have been made from a standard wood structure, various plastics, metals of different types, and composite rackets which are comprised of a combination of any of the above elements.
One of the prime objects in designing and manufacturing a tennis racket is to attempt to provide a good strength to weight ratio which then may be varied in accordance with particular racket requirements. While providing this desirable ratio, the other attributes needed in the racket must also be maintained since, in some structures, the various factors such as stiffness and resiliency, power factor and playability may be damaged if the emphasis is carried too far in the direction of the strength to weight ratio.
Accordingly, it is an object of the present invention to provide a box-type structural member which may be used in tennis rackets and the like which provides a high strength to weight ratio and, at the same time, provides a structure that yields greater latitude in design with the lighter weight providing a range of heretofore unattainable durable, stiff resilient rackets.
Another object of this invention is to provide a structure for use in tennis rackets which is adaptable to selective stiffening during the manufacturing process.
A further object of this invention is to provide a tennis racket having a unique section between the throat and the handle which uses the structure of the present invention.
A still further object of this invention is to provide a racket which has superior dampening properties with a resultant reduction in vibration.
Yet another object of this invention is to provide a structure for a racket wherein a large selective modulus range is available in order to select the particular stress/strain relationship.
Another object of this invention is to provide a racket with a relatively low permanent set which reduces breaks and improves durability.
A further object of this invention is to provide a box-type structural member which allows a great latitude in selection of the stiffness of the bow area.
These and other objects of the invention will become obvious from the following description and the accompanying drawings.